A variety of non-lethal projectiles are known in the prior art. One type of non-lethal projectile is a rubber bullet that is typically used for the purpose of riot control. Rubber bullets, however, have their drawbacks. For example, rubber bullets can penetrate the skin causing severe injury to the target. Additionally, rubber bullets are poor projectiles for marking a target.
Another type of non-lethal projectile is a paint ball. Paint balls are typically used for purposes of marking, such as to mark individuals for future identification without causing injury. Such non-lethal projectiles are used by sportsmen, police, military and other security forces to mark targeted persons, such as those participating in mock war games and other training exercises. Typically, paint balls have a water soluble outer shell, such as a gelatinous material, which allow the shell to safely disintegrate over time when subject to typical environmental conditions. However, such paint balls have several drawbacks. For example, because the typical paint ball is made of a gelatinous material it cannot be filled with a wide variety of components, such as aqueous pigments and/or dyes.
Because of this and other drawbacks, the Assignees of the present invention developed paint ball projectiles made of a plastic, such as polystyrene, which fracture in a predetermined pattern upon impact with a target. U.S. Pat. Nos. 5,254,379 and 5,639,526 (the disclosures of which are incorporated herein by reference in their entirety) provide a plastic paint ball constructed of a linear polymer of sufficient strength to transport, load, and fire out of a compressed gas gun, which is molecularly oriented such that upon application of a force at any impact point on the paint ball shell, the shell fractures in a way that greatly reduces the risk of injury. Further, because the plastic paint ball is not water soluble like a gelatinous one, it is not sensitive to the environment and can be filled with a wide variety of components, including aqueous pigments and/or dyes, powders and solids. While such plastic paint balls effectively mark a target without injury and do not have the drawback of limiting the type of material that can be carried in the paint ball, they may not adequately stun or immobilize a target, as is needed for the purpose of riot control.
More importantly, traditional paint balls, whether the shell is formed from gelatin or plastic, suffer from inaccuracy, especially when launched from a distance greater than 100 feet from the target. This inaccuracy is due, in part, to the spherical shape and smooth surface of the paint ball projectile. The spherical shape creates an irregular, turbulent flow around the projectile causing an unstable flight pattern. Also, when a smooth-surfaced paint ball is fired from a smooth, uniform-bore barrel, the result is a ball generally without spin, which behaves unpredictably. Additionally, due to inherent manufacturing difficulties, most paint ball projectiles are not perfectly spherical. For example, gelatinous paint balls tend to be up to 0.015″ out of round. While plastic shells are usually only about 0.002″ out of round, even this seemingly small oblong shape imparts inaccuracy to the fired paint ball projectile.
Another problem is that the effective range of current paint ball projectiles is very limited. This is because paint balls are typically large projectiles, are not very dense, have a spherical shape and are fired at low muzzle velocities, all of which creates a substantial amount of drag in comparison to the momentum provided to the paint ball upon firing with a compressed gas gun.
In order to solve the problem of non-lethal projectiles to be used for riot control the Assignees of the present invention developed a dual cavity projectile as shown in U.S. Pat. Nos. 6,230,630 and 6,615,739, the disclosure of both being incorporated herein by reference and made a part hereof. The projectiles disclosed in the '630 and '739 patents comprise a first front enclosed cavity in a generally hemispherical portion, and a second rear closed cavity in a generally cylindrical portion. The hemispherical portion has a wall with an inner surface and an outer surface wherein the inner surface forms a hemispheric interior volume, and the cylindrical portion has a wall with an inner surface and an outer surface to form a second interior hemispherical volume having the same general shape and volume as the interior volume of the front hemispherical portion. The two closed cavities operate as the single closed cavity of the traditional round paintball. Accordingly, these projectiles require a bottom wall on the cylindrical portion. The bottom wall operates as a portion of the inner and outer surface of the second interior volume. Typically, in these inventions the front hemispherical closed cavity carries a weighing agent, such as a metal or metal alloy. The metal weighting agent is preferably non-toxic and not environmentally hazardous, such as bismuth. Bismuth weighting agents are non-toxic, pose low risks to the environment, and may be preferred where such considerations are important. The rear hemispherical closed cavity preferably carries a marking agent, or an immobilizing agent, or a combination of a marking agent and an immobilizing agent. Marking agents generally comprise liquid pigments and/or dyes, powder pigments and/or dyes, water soluble pigments and/or dyes, permanent pigments and/or dyes, infra red pigments and/or dyes, ultra violet pigments and/or dyes, pigments and/or dyes that glow in the dark (e.g., a chemiluminescent pigment and/or dye or a phosphorescent pigment and/or dye), and miniature radiotransmitters. Immobilizing agents are used to immobilize a target struck by the projectile. Examples of immobilizing components include liquid irritants, powder irritants, gaseous irritants, pepper powders, tear gas, malodorants, and other noxious chemicals. However, the inventions of the '630 and '739 patents require a dual cavity and a rear bottom wall that closes the rear cavity. As a result, these projectiles are heavy and more costly.
Thus, there remains a need for an inexpensive single cavity projectile that is both lightweight and effective in marking and/or immobilizing a target, and which provides greater accuracy than traditional paint balls for recreational play. The present invention seeks to overcome certain of these limitations and other drawbacks of the prior art, and to provide new features not heretofore available for recreational play. A full discussion of the features and advantages of the present invention is deferred to the following detailed description, which proceeds with reference to the accompanying drawings.